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Alessandro Piras

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

3 papers

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YNIMG Journal 2026 Journal Article

Functional and structural connectivity between the cerebellum and the cortical mirror neuron system: evidence from fMRI and DTI probabilistic tractography

Antonino Errante
Eleonora Sicuri
Cristina Russo
Giuseppe Ciullo
Alessandro Piras
Marzio Gerbella
Leonardo Fogassi

Studies in humans and monkeys have shown that action observation activates not only cortical areas of the mirror neuron system (MNS) but also the cerebellum and other subcortical structures. Cortico-cerebellar circuits are proposed to be involved in the predictive control and simulation of goal-directed observed actions. However, it remains unclear whether cerebellar projections originating from visuo-motor sectors are partially segregated from those starting from purely motor sectors. To address this issue, sixteen healthy participants underwent an fMRI study in which they were required to observe and execute grasping actions. The study allowed to identify cerebellar and thalamic regions predominantly involved in motor execution, as well as regions activated during both observation and execution. Probabilistic tractography and effective connectivity analyses were then used to characterize the projections and functional interactions of these sectors. The cerebellar lobules I-V, dorsal dentate nucleus (DN) and ventrolateral-ventral anterior thalamic nuclei (VL-VA) were mainly active during execution, whereas cerebellar lobule VI, ventral DN, red nucleus (RN) and ventroposterolateral thalamic nucleus (VPL) showed shared activation during observation and execution. At the cortical level, both observation and execution engaged the ventral premotor cortex (PMv) and the inferior parietal lobule (IPL). Tractography revealed that dorsal DN tracts project to RN and VL-VA, terminating in rostral IPL and ventral PMv, while ventral DN projections target RN and VPL, terminating more caudally in IPL and more dorsally in PMv. Effective connectivity analyses showed that execution was associated with increased coupling between DN, RN, VL-VA, and IPL-PMv, while both observation and execution were characterized by enhanced connectivity between DN, RN, VPL, and IPL-PMv. Overall, these findings indicate that cerebellar projections to thalamic and cortical regions involved in action observation and execution are partially segregated from purely motor projections, supporting a cerebellar role in motor simulation during observation and execution of goal-directed actions.

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YNIMG Journal 2025 Journal Article

Predicting imitative performance through cortico-cerebellar circuits: A multivariate and effective connectivity study

Antonino Errante
Giuseppe Ciullo
Settimio Ziccarelli
Alessandro Piras
Cristina Russo
Leonardo Fogassi

The ability to accurately imitate actions requires the contribution of the Mirror Neuron System (MNS) and of prefrontal and cerebellar regions. The present study aimed at investigating whether functional interaction between cortical areas and the cerebellum during the observation of complex bimanual actions can predict individual ability to imitate the same actions. Nineteen healthy participants underwent an fMRI task in which they observed complex bimanual action sequences (paper folding) and subsequently imitated the same sequences. Control conditions included passive observation of bimanual actions, observation of reaching movements, observation of actions without intent to imitate, and observation of natural landscapes. Participants' imitation performance was video-recorded and scored for accuracy. Univariate whole-brain regression, multivariate pattern recognition, and generalized psychophysiological interaction analyses were used to assess whether activation patterns during the observation phase could predict subsequent imitation performance. The results showed that: (i) observing actions during the imitation condition activated parietal, premotor, prefrontal cortex, and lateral cerebellum; (ii) activation levels in the left anterior intraparietal sulcus (aIPS), ventral premotor cortex (PMv), dorsolateral prefrontal cortex (DLPFC), and right lateral cerebellum (CB VI) predicted imitation accuracy; (iii) a bilateral distribution pattern involving aIPS, PMv, DLPFC, and CB VI better predicted imitation performance than a whole-brain approach; (iv) increased effective connectivity between the right CB VI, left aIPS, and left DLPFC during observation-to-imitate condition correlated with higher imitation accuracy. These findings underscore the role of the cerebellum within the MNS in simulating observed actions and enabling their accurate reproduction.

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YNICL Journal 2024 Journal Article

Lesion mapping and functional characterization of hemiplegic children with different patterns of hand manipulation

Antonino Errante
Francesca Bozzetti
Alessandro Piras
Laura Beccani
Mariacristina Filippi
Stefania Costi
Adriano Ferrari
Leonardo Fogassi

Brain damage in children with unilateral cerebral palsy (UCP) affects motor function, with varying severity, making it difficult the performance of daily actions. Recently, qualitative and semi-quantitative methods have been developed for lesion classification, but studies on mild to moderate hand impairment are lacking. The present study aimed to characterize lesion topography and preserved brain areas in UCP children with specific patterns of hand manipulation. A homogeneous sample of 16 UCP children, aged 9 to 14 years, was enrolled in the study. Motor assessment included the characterization of the specific pattern of hand manipulation, by means of unimanual and bimanual measures (Kinematic Hand Classification, KHC; Manual Ability Classification System, MACS; House Functional Classification System, HFCS; Melbourne Unilateral Upper Limb Assessment, MUUL; Assisting Hand Assessment, AHA). The MRI morphological study included multiple methods: (a) qualitative lesion classification, (b) semi-quantitative classification (sq-MRI), (c) voxel-based morphometry comparing UCP and typically developed children (VBM-DARTEL), and (d) quantitative brain tissue segmentation (q-BTS). In addition, functional MRI was used to assess spared functional activations and cluster lateralization in the ipsilesional and contralesional hemispheres of UCP children during the execution of simple movements and grasping actions with the more affected hand. Lesions most frequently involved the periventricular white matter, corpus callosum, posterior limb of the internal capsule, thalamus, basal ganglia and brainstem. VMB-DARTEL analysis allowed to detect mainly white matter lesions. Both sq-MRI classification and q-BTS identified lesions of thalamus, brainstem, and basal ganglia. In particular, UCP patients with synergic hand pattern showed larger involvement of subcortical structures, as compared to those with semi-functional hand. Furthermore, sparing of gray matter in basal ganglia and thalamus was positively correlated with MUUL and AHA scores. Concerning white matter, q-BTS revealed a larger damage of fronto-striatal connections in patients with synergic hand, as compared to those with semi-functional hand. The volume of these connections was correlated to unimanual function (MUUL score). The fMRI results showed that all patients, but one, including those with cortical lesions, had activation in ipsilesional areas, regardless of lesion timing. Children with synergic hand showed more lateralized activation in the ipsilesional hemisphere both during grasping and simple movements, while children with semi-functional hand exhibited more bilateral activation during grasping. The study demonstrates that lesion localization, rather than lesion type based on the timing of their occurrence, is more associated with the functional level of hand manipulation. Overall, the preservation of subcortical structures and white matter can predict a better functional outcome. Future studies integrating different techniques (structural and functional imaging, TMS) could provide further evidence on the relation between brain reorganization and specific pattern of manipulation in UCP children.

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